Cyclotol and thermite explosive composition



United States Patent ()fifice 3,297,503 Patented Jan. 10, 1967 CYCLOTOL AND THERMITE EXPLOSIVE COMPOSITION :Paul. .O! Hofimann, Maplewood, and Irving .L. iKintish,

The invention described herein may be manufactured and :used by or for the Government for governmental Ont Thisqtinvention relatesto explosives and more particularly concerns cyclotol type explosives modified by thermites.

The well-known thermite process is based on the reaction of. various metallic oxides with a specified metal resultingin the oxidation of the metal to its oxide and the reduction of the metallic oxide to the free metal, the reaction being extremely exothermic and oxygen selfsustaining.

The standard thermite reaction is:

and the; chemical constituents involved therein, as in all thermite reactions, are stoichiometrically balanced. Ex-

. amples. ofgother thermite reactions are:

Wexhave discovered that when certain thermites are incorporated in an explosive such as cyclotol, for example, which contains 60 parts of cyclotrimethylenetrinitramine, hereinafter referred to as RDX, and 40 parts of TNT, and about 1 part of a suitable hinder, the resultant explosive is characterized by good positive afterburning and extended fireballing. Afterburning is a desirable feature in:many ordnance explosives, as is Well known, since it maintains the pressure peak and duration of impulse of the explosion for several milliseconds after the primary explosion. Fireballing is a phenomenon wherein the explosiverains down molten metal particles, and when exploded at lower altitudes, will comprise a highly potentialthazard to; the enemy in jungle and guerilla warfare, in initiating conflagration-s, in secondary ground casualties, and thetlike.

It is therefore the principal object of this invention to provide. an explosive having the aforementioned advantages.

Other and further objects of the invention will be apparent to. those skilled in the art upon study of this disclosure;

In each of the examples following, the particular thermite was madein accordance with the procedure outlined belowv 100 grams of the thermite in stoichiometric proportions are thoroughly mixed in a suitable crucible of smooth, refractory material such as porcelain, alundum, TiO ZrO mullite, and the like and placed in an electric bench furnace and heated at a rate of about 10 i to 15 C./min. until the melting point of the metal involved is attained, the temperature being held thereat for about 5 to, minutes. The metal particle size will preferably range between 5 to microns and the oxide particle size will have a range of about 0.1 to 1 micron. The furnace is then allowed to cool gradually to room temperature and the crucibleremoved from the furnace.

purposeswithout the payment to us of any royalty there- 7 The agglomerated thermite may now 'be removed from the crucible and carefully granulated, as by ball milling, for example, such that of the thermite will pass through a 325 mesh screen (44 microns).

The thermite will constitute about 5 to 25 weight percent of the explosive but preferably will range between about 8 to 10%. If higher percentages of thermite are employed, the resultant explosive will yield lowerblast with greater fireballing effects. Conversely, when lower percentages of thermite are incorporated into the cyclotol type composition, higher blast and afterburning will be achieved at the expense of less fireballing.

EXAMPLE I Grams RDX 60 TNT 40 Fe 0 5.98 Al 2.02

EXAMPLE II Grams RDX 60 TNT 40 B 0 7.99 Zr 2.01

EXAMPLE III Grams RDX 60 TNT 40 Li 2.26

EXAMPLE 1V Grams RDX 60 TNT 40 EXAMPLE V Grams RDX 6O TNT 40 M11304 EXAMPLE VI Grams RDX 60 TNT 40 Al 5.37 V 0 4.63

In Examples II through VI, the procedure is identical with that described under Example I.

The following table indicates blast superiority and afterburning elfects of our compositions over cyclotol when tested using standard calorimetric procedures, the cyclotol being assigned the numerical value of 100.

3 Table I.-Blast efiectiveness Numerical Composition: value Cyclotol 100 Example I 105 Example II 106 Example III 108 Example IV 106 Example V 110 Example VI 115 In the practice of our inventive composition, the cyclotol may be ignited by a standard tetryl booster and detonator, a #8 blasting cap, etc. When sufficient heat is produced therefrom, the oxygen self-sustaining thermite composition is ignited. Our composition will provide for increased blast and fireballing, and, as above mentioned, increasing the amount of thermite results in increased fireballing eifects. Further, our inventive compositions do not deleteriously affect the impact sensitivity, vacuum stability or detonation rate of the cyclotol.

It should be understood, of course, that the foregoing disclosure relates to only preferred embodiments of our compositions and other thermite and explosive compositions may be used without departing from the spirit and scope of the invention as set forth in the appended claims.

We claim: 1. A high blast, good afterburning and good fireballing explosive composition comprising cyclotol and thermite, said thermite being selected from the group consisting of Al+Fe O Zr+B O Li+MoO Li+WO Al+Mn O and 2. The composition of claim 1 further characterized by said explosive composition comprising about 60 parts RDX, parts TNT and about 5 to 25 parts of one of said thermites.

3. The composition of claim 2 further characterized by said thermite preferably comprising 8 to 10 parts by weight of said explosive composition.

References Cited by the Examiner UNITED STATES PATENTS 2,424,937 7/1947 Linzell 14937 2,640,770 6/1953 Magram et al 14937 2,955,535 10/1960 Show et al l4937 X 3,050,409 8/1962 Bayer 14937 X 3,110,638 11/1963 Murphy et a1 149-37 X 3,150,020 9/1964 Kilmer 14937 3,160,097 12/1964 Colburn et a1 14937 X CARL D. QUARFORTH, Primary Examiner.

L. DEWAYNE RUTLEDGE, Examiner.

S. I. LECHERT, JR., Assistant Examiner. 

1. A HIGH BLAST, GOOD AFTERBURNING AND GOOD FIREBALLING EXPLOSIVE COMPOSITION COMPRISING CYCLOTOL AND THERMITE, SAID THERMITE BEING SELECTED FROM THE GROUP CONSISTING OF AL+FE2O3, ZR+B2O3, LI+MOO3, LI+WO3, AL+MN3O4, AND AL+V2O5. 